MABERY. 



SULPHUR PETROLEUMS. 53 



It is peculiar that in distillation under atmospheric pressure as 

 well as in vacuo the lowest fraction from the Canadian oil is heavier 

 than that from Ohio oil, while the next following distillates are re- 

 versed in the order of their specific gravity. Under the influence of 

 vacuum distillation a large portion of the heavier constituents of the 

 residue above 350°, under atmospheric pressure, are reduced in boil- 

 ing points to such an extent that the specific gravity of the lower frac- 

 tions is very considerably increased. Referring to the specific gravity 

 of the fractions from the Apscheron oil, page 48, it will be seen that 

 the corresponding fractions in vacuo from the Canadian oil are much 

 heavier, and the residue is much smaller. The ditFerences between the 

 weights collected at different temperatures in the Canadian and Ohio 

 petroleum also confirm the marked variation in composition already 

 referred to, and an explanation must evidently be sought in the larger 

 quantities of the series C2H2 „+ o in the fractions below 150° from 

 Ohio oil, and the greater quantity of the heavier oils of the series 

 C„H2« and similar series in distillates from Canadian oil above this 

 point. 



The percentages of sulphur in these distillates were also determined : 



—100= 100^-150° 150^-200= 200-^-250= 250^-300= 300^-350^ Residue. 



Sulphur 0.25 0.45 0.47 0.75 0.78 0.81 0.83 



When distilled without much decomposition the sulphur compounds 

 in Canadian oil collect in smaller quantities iu the lower distillates 

 than is the case in Ohio oil. 



Determinations were made of the per cent of bromine absorbed by 

 the vacuum distillates : — 



100° 100^-150= 150°-200= 200^-250= 250'=-300= 300^-350= Residue. 



Bromine abs. 3.25 4.59 6.2 8.2 15.8 25.82 



Bromine abs. 



atm. pressure 0.67 1.12 3.49 8.39 14.4 17.8 



Br. abs. Ohio 250°-360° 



oil, vac. dist. 4.57 6.60 7.08 24.38 



There is a marked difference in bromine absorption between the 

 distillates collected in vacuo and those collected under atmospheric 

 pressure. The capacity for absorbing bromine in the distillates from 

 Canadian oil is greatly increased in the lower fractions by vacuum 

 distillation, and this difference is even more noticeable in Ohio oil. 

 It is probably due to the smaller amounts of Canadian oil distilling at 

 lower temperatures under atmospheric pressure. The larger quanti- 



